Operating unit for electrical appliances

Abstract

The invention relates to an operating unit for operation of household appliances, especially for operation of a hob or a washing machine. In this connection, operating elements are arranged on an electrically conductive operating plate, by which they are capacitively coupled with a receiving device that is located in or at the household appliance. Transmission of the operation of the operating elements to the receiving device takes place by detection a load change in the receiving device, the load change being caused by the operating elements.

1 . An operating plate for operation of a household appliance, comprising an electrically conductive plate with at least one operating element arranged at or in the plate,
 wherein the operating element comprises at least one first electrode and at least one second electrode,   wherein the at least one second electrode constitutes a coupling capacitance with ground,   wherein the at least one first electrode is capacitively couplable with the electric conductive plate,   wherein operation of the operating element is capacitively transmitted to a receiving device, and   wherein a load of the receiving device corresponds to the ground-coupling capacitance of the at least one second electrode.   
     
     
         2 . The operating plate according to  claim 1  wherein the operating element comprises at least one modulation device, and the combination of the at least one first electrode, the at least one second electrode and the modulation device constitutes an electrode device. 
     
     
         3 . The operating plate according to  claim 1  wherein the operating element is provided such that a change in the ground-coupling capacitance of the second electrode causes a change in the load of the receiving device. 
     
     
         4 . The operating plate according to  claim 1  wherein an alternating electric field coupled into the conductive plate is couplable at least partially into the first electrode of the electrode device and the modulation device is designed to modulate an electric variable of the electrode device, depending on the change in the coupling capacity of the second electrode with ground. 
     
     
         5 . The operating plate according to  claim 4  wherein the modulation comprises an amplitude modulation. 
     
     
         6 . The operating plate according to  claim 2  wherein the modulation device comprises one of a resonant circuit and a frequency divider. 
     
     
         7 . The operating plate according to  claim 1  wherein each electrode device is designed to cause a frequency modulation of the electric variable, the frequency modulation being indicative of the respective electrode device. 
     
     
         8 . The operating plate according to  claim 1  wherein an electric field emitted by the receiving device is couplable into the electrically conductive plate and a modulation of the electric variable of the electrode device causes a change in the load at the receiving device. 
     
     
         9 . The operating plate according to  claim 1  wherein the electrically conductive plate comprises two segments, which are separated from each other by an insulator, the at least one first electrode of the operating element being arranged at a first segment, the at least one second electrode of the operating element being arranged at a second segment, and one of the two segments being coupled with ground. 
     
     
         10 . The operating plate according to  claim 1  wherein an insulator is provided between the electric conductive plate and the least one operating element. 
     
     
         11 . An operating panel for a household appliance, the panel comprising a number of operating elements wherein the operating elements are approach-sensitive and the operating panel is exchangeable. 
     
     
         12 . The operating panel according to  claim 11  wherein the individual operating elements of the operating panel are optically coupled with a control unit of the household appliance by a respective light guide. 
     
     
         13 . The operating panel according to  claim 11  wherein the operating elements of the operating panel is couplable with the control unit of the household appliance so as to transmit a signal to the control unit. 
     
     
         14 . The operating panel according to  claim 11  wherein a operating element comprises at least one first electrode, which is part of a first electrode device, the first electrode device being formed by the at least one first electrode and by at least one second electrode, and the first electrode device is couplable with a modulation device. 
     
     
         15 . The operating panel according to  claim 14  wherein the first electrode device is capacitively couplable with an evaluating circuit. 
     
     
         16 . The operating panel according to  claim 15  wherein an electric field emitted by an evaluating circuit is couplable into the second electrode of the first electrode device, the coupled-in electric field is modulated by the modulation device, the modulated signal is fed back by the second electrode device, preferably by means of load modulation, to the evaluating circuit, and the feedback signal is detected and evaluated by the evaluating device. 
     
     
         17 . The operating panel according to  claim 16  wherein an object approaching the first electrode of the first electrode device causes a modulation, preferably an amplitude modulation of the coupled-in electric field by the modulation device. 
     
     
         18 . The operating panel according to  claim 14 , comprising several operating elements, the operating elements being designed to be distinguishable by the evaluating device. 
     
     
         19 . The operating panel according to  claim 14  wherein the evaluating circuit is coupled with the control unit of the washing machine so as to transmit information regarding the activated and/or selected operating elements. 
     
     
         20 . A household appliance, comprising an operating panel according to  claim 11 . 
     
     
         21 . A receiving device, designed to cooperate with an operating plate according to  claim 1 , the receiving device comprising:
 an electric circuit for generating an electric field, which is couplable into the operating plate and/or the operating panel, and means for evaluating an electric variable of the electric circuit.   
     
     
         22 . The receiving device according to  claim 21  wherein the evaluation comprises detection of a load change in the electric circuit. 
     
     
         23 . The receiving device according to  claim 22  wherein the load change comprises at least one frequency-modulated part and the evaluation comprises a separation of the frequency-modulated parts of the load change. 
     
     
         24 . The receiving device according to  claim 21  wherein the electric circuit comprises:
 an LC resonant circuit with a signal generating circuit, preferably a LC resonant circuit having a high quality-factor, for the generation of the electric field, and 
 a second electrode device, connected in parallel with the LC resonant circuit wherein the capacitance of the electrode device constitutes a part of the resonant circuit capacitance of the LC resonant circuit and the electric field generated by the LC resonant circuit is emittable by the electrode device. 
 
     
     
         25 . The receiving device according to  claim 21 , comprising means by which a device to be operated is adjusted in accordance with an operation of the at least one operating element.